From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Comparing the efficiency, output, and design of a Lucas dynamo against an in-house model.
| Identifier | ExFiles\Box 182\M19\ img017 | |
| Date | 9th February 1931 | |
| To E.{Mr Elliott - Chief Engineer} from EFC. c.c. to. Mr. HS.{Lord Ernest Hives - Chair} ORIGINAL EFC1/AD9.2.31. X.6100. Lucas Dynamo. We have received your 28/M7.2.31. Probably at the time of writing your note you had not received our report EFC3/AD2.2.31. We ourselves feel that there is actually little to be gained from an examination and comparison of a standard Lucas car dynamo that we do not already know. We know well the effect of the Lucas arrangement of windings - we had a good deal of experience of it when we used to use Lucas E.575 machines. Although we have little doubt that the present Lucas machines are more efficient than the earlier ones, so also are our own machines a good deal more efficient and we should say that it is very unlikely that any Lucas machine shows more peak output for a given weight, cutting in point and temperature rise than one of our own machines. Whilst acknowledging the fact of the better maintenance at speed of the output with the Lucas arrangement of windings, we should still be of the opinion that the introduction, to secure this, of the considerably greater wiring and switching complication is only worth it when it has been fully shown that there is no other better and simpler way of attaining the same result, assuming in each case no increase in size and weight. We are quite ready to obtain one of the machines and make the tests and examination proposed, but we feel that a careful perusal of our EFC3/AD2.2.31 will put the matter in a somewhat different light particularly in view of the fact that a Lucas machine of mainly similar design has already been tested and a result given, which result does not show any decidedly bigger output than our own even though the weight is 5 1/4 lbs greater. In any case before taking this step we feel it more expedient to await the result of the test on the special armature with wider and deeper slots because we do expect from this armature an improvement in the output curve generally i.e. some improvement from all three points of view simultaneously, these being cutting in point, peak output and maintenance of output at speed. Is it possible for you to let us know the revolutions per mile at which your dynamo is driven on your car? E.F.C. | ||